How to set Acct-Interim-Interval for all users ?

Hello, How to add the Acct-Interim-Interval attribute for all users ? I'm using freeradius 3 on centos 7. I know that one way is to insert it into the radreply table or the radgroupreply table. If possible, where and how to set it for all users in the config files under /etc/raddb, so I can avoid adding it many times in the mysql tables ? Thank you.